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ABSTRACT: The capabilities of two types of terahertz sources based on stimulated Smith-Purcell radiation of electrons in open cavities are discussed. A series of developed pulsed orotrons provides coherent radiation with an output power of 1-0.1 W in the frequency range of 90-410 GHz, with high frequency stability and broad-band electromechanical frequency tuning. A promising alternative source with smaller currents than that in orotrons is a frequency multiplier based on excitation of a surface wave of a periodic structure and Smith-Purcell radiation of arising electron bunches inside the orotron cavity. In contrast to a number of works where only an open grating is used, exploiting a cavity enables a stimulated radiation process with a much higher power. The developed theory demonstrates the possibility of single-mode generation in such multipliers with wide electron beams.
IEEE Transactions on Plasma Science 07/2010; · 1.17 Impact Factor
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ABSTRACT: In this paper, the low-voltage pulse orotron generators of the short millimeter and long submillimeter waves with power level up to 1 W have been developed. Some methods of frequency and power enhancement are proposed.
Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves and Workshop on Terahertz Technologies, 2007. MSMW '07. The Sixth International Kharkov Symposium on; 07/2007
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ABSTRACT: We have developed a series of low-voltage orotrons operated in the short-wave part of the millimeter and long-wave section
of the submillimeter wavelength range. The use of an open resonator as the electrodynamic system of the orotron ensures high
stability of the radiation frequency and a wide band of frequency tuning. The output orotron power achieved experimentally
amounts to hundreds of milliwatts, which is sufficient for many promising spectroscopy methods.
Radiophysics and Quantum Electronics 10/2006; 49(11):866-871. · 0.71 Impact Factor
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ABSTRACT: Summary form only given. Electron vacuum sources of coherent terahertz radiation are being now intensively developed at the Institute of Applied Physics (IAP). These devices are intended for wide-spread utilizing in many research and technical applications including spectroscopy, diagnostics of different media, communications, material processing etc. In this presentation, two types of promising THz electron oscillators, namely orotrons and gyrotrons, will be discussed. The orotrons have been realized at the IAP in collaboration with the Institute of Metrology for Time and Space and Institute of Spectroscopy. The operation of the orotron (or diffraction radiation generator) is based on the stimulated Smith-Purcell radiation of a rectilinear electron beam in a selective open cavity which has a periodic structure on one of its mirrors. At the moment, a series of the low-voltage (0.5-5 kV) orotrons developed generate in the frequency range of 0.1-0.4 THz with output power of 1.0-0.1 W and typical electrical-mechanical frequency tuning within an octave. Using same voltage, orotrons can enable higher power and frequency stability than BWOs that are most widespread devices within entire terahertz range. Orotrons with relativistic electron beams, which are studied at the IAP, are capable to provide significantly higher pulse THz power (up to MW level at ns pulse duration). Both conventional and large-orbit gyrotrons (LOGs) are also under development at the IAP The LOGs are based on the same mechanism of stimulated cyclotron radiation of electrons as conventional gyrotrons, but they are more selective when operating at higher cyclotron harmonics. Correspondingly, they work at lower magnetic fields. At the same time significantly more complicated electron guns are needed for the LOGs to provide appropriate axis-encircling electron beams. Such beams with electron energy 50-250 keV and very high compression have been obtained and powerful selective generation at 1st-5th cyclot-
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ron harmonics have been demonstrated in the IAP at millimeter and submillimeter waves. When operating at the third cyclotron harmonic generation with power level of 10-20 kW has been obtained in the range of 0.3-0.42 THz. Another prospective way for developing THz sources, that will be also presented, is realization of gyro-multipliers with self-exciting LF sections and HF sections operating at high cyclotron harmonics
Plasma Science, 2006. ICOPS 2006. IEEE Conference Record - Abstracts. The 33rd IEEE International Conference on; 07/2006
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ABSTRACT: A highly sensitive intracavity millimeter-wave spectrometer was developed for the investigation of the absorption spectra of van der Waals complexes in a supersonic jet. The key element of the spectrometer is a tunable oscillator, called OROTRON, which generates the millimeter-wave radiation through the interaction of an electron beam with the electromagnetic field of a high quality (Q ≈ 104) Fabry–Perot resonant cavity. This cavity consists of a movable spherical mirror and a fixed planar mirror with the periodic structure imprinted on its surface. The electron beam moves along the periodic structure of the plane mirror. This part separated from the rest of the resonator by a mica foil is kept under ultrahigh vacuum conditions. The molecular jet is injected by a pulsed valve into the other part of the resonator. The absorption in the jet is sensitively detected by measuring the electric current in a special collector circuit of the OROTRON. The spectral purity of the OROTRON radiation is 10–15 kHz providing the capability of sub-Doppler spectral resolution without phase locking. An increase in sensitivity of a factor of about 100 in comparison with the usual single pass arrangement was evaluated from the measurements of the absorption lines of the CO rare isotopomers, the Ar–CO and Ne–CO van der Waals complexes. The high sensitivity, wide spectral range, and simple tunability of the spectrometer make it a very efficient tool for the searching of weakly absorbing species in a jet. © 2001 American Institute of Physics.
Review of Scientific Instruments 05/2001; 72(6):2535-2542. · 1.37 Impact Factor
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ABSTRACT: Doppler-free two-photon rotational transitions J = 13<--<--11 and J = 12<--<--10 of OCS and J = 8<--<--6 and J = 7<--<--5 of CHF (3) were detected in the frequency range 134-156 GHz, using a novel, highly sensitive intracavity-jet technique. The sub-Doppler narrowing of the observed peaks (down to 40 kHz full width at half maximum as compared to 300 kHz of the Doppler width) demonstrates the potential of this new technique for high precision millimeter wave spectroscopy. The possibilities of the further reduction of the two-photon absorption line widths are considered.
Physical Review Letters 03/2001; 86(10):2002-5. · 7.37 Impact Factor
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ABSTRACT: The design and operation of a gas millimetre-wave spectrometer based on a tunable generator orotron are presented. The absorption cell occupies a part of the high quality (Q approximately=104) orotron Fabry-Perot cavity. The limit of sensitivity gamma min approximately=(3-5)*10-10 cm-1 has been achieved with source frequency modulation at the output band of a receiver of 1 Hz. The narrow spectral width of the orotron radiation (10-15 kHz without locking) provides the Doppler resolution of spectral lines. An absorption signal of gas under investigation is detected by variations of the collector current of the orotron. New results on rotational transition of SiH4 in a vibrational dyad v2/v4 with the absorption coefficient gamma approximately=10-8 cm-1 are briefly given as an illustration of the sensitivity of this spectrometer.
Measurement Science and Technology 12/1998; 3(9):873. · 1.49 Impact Factor
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ABSTRACT: Results of a theoretical analysis of the density of starting currents of
surface waves in an orotron for different electron-beam voltages and
different periods of the comb-type periodic structure are presented with
reference to the design of backward-wave tubes. Good agreement is found
between the theoretical results and experimental data on the voltage
dependences of the starting currents of orotron oscillations and
surface-wave starting currents. It is concluded that the results
obtained can be used to control the excitation of surface waves in
orotrons and maintain the stable operation of orotrons in the
appropriate high-frequency range.
Radiotekhnika i Elektronika. 04/1985; 30:994-997.
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ABSTRACT: Large orbit gyrotron (LOG) provides output power of 40 kW at the frequency of 240 GHz. Orotrons radiate at frequencies of 100-380 GHz with power of 50-200 mW and high frequency stability. In a LOG, electron-wave interaction at high cyclotron harmonics is more selective than in conventional gyrotrons that allows achieving higher frequencies. Higher output power and higher frequency stability can be obtained in orotrons in comparison with conventional BWOs due to use of open cavities.
Infrared and Millimeter Waves, 2004 and 12th International Conference on Terahertz Electronics, 2004. Conference Digest of the 2004 Joint 29th International Conference on;
